Cool Carl Franklin started his Grok Talk on Consuming RSS Feeds with "Hello, I'm Carl Franklin and all of the code you see here today will have been generated by a tool." You knew that he knew he just told a great inside joke but he didn't let on.
As for its origin, most .NETers probably already know this, but you'll find this statement at the beginning of a Web Service reference source file. Here's an example.
//------------------------------------------------------------------------------
// <auto-generated>
// This code was generated by a tool.
// Runtime Version:2.0.50215.44
//
// Changes to this file may cause incorrect behavior and will be lost if
// the code is regenerated.
// </auto-generated>
//------------------------------------------------------------------------------
Now THAT'S good clean geek humor!